This invention relates to a polarizing eyeglass device, and more particularly to a technical field for improving the compatibility in viewing an image displayed on an image display screen of a stereoscopic image display apparatus.
Various methods have been proposed for representing a stereoscopic image using a liquid crystal display screen. For example, a method is available wherein a polarizing eyeglass device is used to view an image displayed on an image display screen of a stereoscopic image display apparatus as a stereoscopic image making use of the parallax of the two eyes.
FIG. 32 shows an exemplary one of conventional stereoscopic image display apparatus and polarizing eyeglass devices for viewing a stereoscopic image (refer to Patent document 1: Japanese Patent Laid-Open No. 2002-196281 (pages 5 to 6, FIG. 3)).
Referring to FIG. 32, an image display screen b in the form of liquid crystal display screen of a stereoscopic image display apparatus a in the form of a liquid crystal display apparatus has a plurality of horizontal areas S divided in a vertical direction. The horizontal areas S include first areas Sa and second areas Sb arranged, for example, alternately from above. For example, images cR for the right eye are individually displayed in the first areas Sa while images cL for the left eye are individually displayed in the second areas Sb.
A polarizing plate d having, for example, a leftwardly upwardly inclined angle of polarization is adhered to the image display screen b. A half-wave plate e for changing the polarization direction of polarized light emitted from a second area Sb through the polarizing plate d by 90° is adhered to the region of a face of the polarizing plate d on the side facing the viewer which corresponds to each of the second areas Sb. Consequently, the polarization angle of polarized light emitted from the second areas Sb through the polarizing plate d is changed into a rightwardly upwardly inclined polarization angle by the half-wave plates e.
The polarizing eyeglass device f includes a horizontally elongated polarizing plate g having, for example, a rightwardly upwardly inclined polarization angle. A half-wave plate h having an optical axis orthogonal to that of the half-wave plates e of the stereoscopic image display apparatus a is adhered to a face of the right half of the polarizing plate g on the side facing the image display screen b.
If the polarizing eyeglass device f is used for viewing the image display screen b of the stereoscopic image display apparatus a configured as described above, then the left eye El of the viewer who looks through the polarizing plate g cannot view the right eye images cR because the polarization angles of the polarizing plate d of the stereoscopic image display apparatus a and the polarizing plate g of the polarizing eyeglass device f are orthogonal to each other. On the other hand, the left eye El of the viewer can view the left eye images cL. This is because the polarization direction of the polarized light emitted from the second areas Sb through the polarizing plate d is changed by 90° by the half-wave plates e present between the polarizing plates d and g whose polarization angles are orthogonal to each other.
On the other hand, the right eye Er of the viewer who looks through the polarizing plate g cannot view the left eye images cL. This is because, although the polarization direction of the polarized light emitted from the second areas Sb through the polarizing plate d is changed by 90° by the half-wave plates e present between the polarizing plates d and g whose polarization angles are orthogonal to each other, the polarization direction of the polarized light having been changed in this manner is changed back to the original polarization direction by the half-wave plate h which has the orthogonal optical axis. In contract, the right eye Er can view the right eye images cR. This is because the polarization direction of the polarized light emitted from the second areas Sb through the polarizing plate d is changed by 90° by the half-wave plate h present between the polarizing plates d and g whose polarization angles are orthogonal to each other.
Accordingly, the left eye El views only the left eye images cL while the right eye Er views only the right eye images cR. Therefore, the viewer can view a stereoscopic image assembled from the left eye images cL and the right eye images cR.
Also another stereoscopic image display apparatus is available which includes polarizing plates having polarization directions different from those described above. An exemplary one of such conventional stereoscopic image display apparatus and polarizing eyeglass devices for viewing a stereoscopic image as just mentioned is described below with reference to FIG. 33.
An image display screen j in the form of liquid crystal display screen of a stereoscopic image display apparatus i in the form of a liquid crystal display apparatus has a plurality of horizontal areas S divided in a vertical direction. Right eye images cR are displayed in first areas Sa of the horizontal areas S while left eye images cL are displayed in second areas Sb of the horizontal areas S.
A polarizing plate k having, for example, a rightwardly upwardly inclined angle of polarization is adhered to the image display screen j. A half-wave plate l for changing the polarization direction of polarized light emitted from a second area Sb through the polarizing plate k by 90° is adhered to that region of a face of the polarizing plate k on the side facing the viewer which corresponds to each of the second areas Sb. Consequently, the polarization angle of polarized light emitted from the second areas Sb through the polarizing plate k is changed to a leftwardly upwardly inclined polarization angle by the half-wave plates l.
The polarizing eyeglass device m includes a horizontally elongated polarizing plate n having, for example, a leftwardly upwardly inclined polarization angle. A half-wave plate o having an optical axis orthogonal to that of the half-wave plates l of the stereoscopic image display apparatus i is adhered to a face of the right half of the polarizing plate n on the side facing the image display screen j.
If the polarizing eyeglass device m is used to view the image display screen j of the stereoscopic image display apparatus i, then the left eye El of the viewer who looks through the polarizing plate n cannot view the right eye images cR. This is because the polarization angles of the polarizing plate k of the stereoscopic image display apparatus i and the polarizing plate n of the polarizing eyeglass device m are orthogonal to each other. On the other hand, the left eye El of the viewer can view the left eye images cL. This is because the polarization direction of the polarized light emitted from the second areas Sb through the polarizing plate k is changed by 90° by the half-wave plates l present between the polarizing plates k and n whose polarization angles are orthogonal to each other.
On the other hand, the right eye Er of the viewer who looks through the polarizing plate n cannot view the left eye images cL. This is because, although the polarization direction of the polarized light emitted from the second areas Sb through the polarizing plate k is changed by 90° by the half-wave plates l present between the polarizing plates k and n whose polarization angles are orthogonal to each other, the polarization direction of the polarized light having been changed in this manner is changed back to the original polarization direction by the half-wave plate o which has the orthogonal optical axis. In contract, the right eye Er can view the right eye images cR. This is because the polarization direction of the polarized light emitted from the second areas Sb through the polarizing plate k is changed by 90° by the half-wave plate o present between the polarizing plates k and n whose polarization angles are orthogonal to each other.
Accordingly, the left eye El views only the left eye images cL while the right eye Er views only the right eye images cR. Therefore, the viewer can view a stereoscopic image assembled from the left eye images cL and the right eye images cR.
In the conventional stereoscopic image display apparatus a and i, however, the inclinations of polarized light by the polarizing plates d and k are different from each other. Therefore, the stereoscopic image display apparatus a and i require the polarizing eyeglass devices f and m for exclusive use different from each other as described above, respectively. Consequently, the stereoscopic image display apparatus a and i are poor in compatibility and require a high cost as much.
Further, if a polarizing eyeglass device prepared for viewing a stereoscopic image is not compatible with a stereoscopic image display apparatus which displays the image to be viewed, then the viewer cannot view the stereoscopic image disadvantageously.